Liquid crystal display device and method for manufacturing the same

ABSTRACT

As a substrate gets larger, time of manufacture is increased due to the repetition of film formations and etchings; waste disposal costs of etchant and the like are increased; and material efficiency is significantly reduced. A base film for improving adhesion between a substrate and a material layer formed by a droplet discharge method is formed in the invention. Further, a manufacturing method of a liquid crystal display device according to the invention includes at least one step for forming the following patterns required for manufacturing a liquid crystal display device without using a photomask: a pattern of a material layer typified by a wiring (or an electrode) pattern, an insulating layer pattern; or a mask pattern for forming another pattern.

TECHNICAL FIELD

The present invention relates to a semiconductor device having a circuitthat is composed of a thin film transistor (hereinafter referred to asTFT) and a method for manufacturing the semiconductor device. An exampleof the semiconductor device is electronic device having anelectro-optical device typified by a liquid crystal display device asone of its parts.

In this specification, the term semiconductor device refers to devicesthat function by utilizing semiconductor characteristics. Further,electro-optical devices, semiconductor circuits, and electronic devicesare all regarded as semiconductor devices.

BACKGROUND ART

In late years, a technology for forming a thin film transistor (TFT)using a semiconductor thin film (a thickness of around severalnanometers to several hundred nanometers) formed over a substrate havingan insulating surface has been attracting attention. Thin filmtransistors are broadly applied to electronic devices such as an IC oran electro-optical device, and are particularly developed as switchingelements for image display devices at a rapid rate.

Conventionally, a liquid crystal display device is known as an imagedisplay device. Active matrix liquid crystal display devices are mostlyused since they can offer higher definition images in comparison withpassive matrix liquid crystal display devices. As to an active matrixliquid crystal display device, an image is generated on a screen bydriving pixel electrodes arranged in matrix. Specifically, opticalmodulation of a liquid crystal layer disposed between a pixel electrodeand a counter electrode is performed by applying voltage between theselected pixel electrode and a counter electrode corresponding to thepixel electrode. The optical modulation is recognized as an image by anobserver.

The application range of such an electro-optical device of an activematrix type has been broaden, and it is required to make the deviceachieve higher definition, higher open area ratio, and higherreliability as well as to make the screen have a larger area. Further,requirements for improvements in productivity and cost minimization arealso increased.

DISCLOSURE OF INVENTION

In manufacturing the above active matrix electro-optical device, stepsof forming a thin film by sputtering or the like and patterning byphotolithography are repeated thereby forming a TFT. As thephotolithography technique, a photomask is used to form a photoresistpattern to be a mask for an etching process on a substrate.

In the case of using such a mask, steps of resist application, prebake,exposure, development, postbake, or the like and steps such as filmformation of a coating and etching performed before/after the prescribedsteps, and further steps of resist removal, washing, and drying, and thelike are additionally required. Therefore, the manufacturing process cannot be prevented from being complicated.

In particular, as a substrate that is to be a base material gets larger,time of manufacture is increased due to the repetition of film formationand etching; waste disposal costs of etchant and the like are increased;and material efficiency is significantly reduced.

In view of the above problems, it is an object of the present inventionto provide a manufacturing method of an electro-optical device by whichthe manufacturing cost can be reduced.

A manufacturing method of a liquid crystal display device according tothe invention includes at least one or more of steps for forming thefollowing patterns required for manufacturing a liquid crystal displaydevice without using a photomask: a pattern of a material layer typifiedby a wiring (or an electrode) pattern, an insulating layer pattern; or amask pattern for forming another pattern.

A pattern of a material layer is formed by a droplet discharge method(for example, ink-jet method).

In addition, the invention provides a technology for easily obtaining anelectrical connection between multi-layer wirings.

Specifically, the invention provides a technology for connectingmulti-layer wirings without forming a contact hole having a high aspectratio (ratio of the diameter to the depth of a contact hole) usingphotolithography. In a portion where the upper-layer wiring iselectrically connected to the lower-layer wiring, a projection(hereinafter, also referred to as a “plug” or a “pillar”) is provided onthe lower-layer wiring. The projection may be a columnar conductivemember or a member which is a stack of conductive members repeatedlyapplied by a droplet discharge method. Further, after an interlayerinsulating film is formed by a coating method, the projection is exposedby etch back. Thus, the lower-layer wiring can be electrically connectedwith the upper-layer wiring through the projection.

As another method, a contact hole can be formed simultaneously with theformation of an interlayer insulating film by selectively forming theinterlayer insulating film by a droplet discharge method.

As still another method, a projection formed with a liquid repellentorganic film is provided on a lower-layer wiring in a portion where aconnection between an upper-layer wiring and a lower-layer wiring ismade. Further, after forming an interlayer insulating film by coating,only the projection is removed; thus, a contact hole can be formed.Then, an upper-layer wiring is formed so as to close the contact hole.

A liquid crystal display device disclosed in this specification of theinvention includes: a thin film transistor including a gate electrodeformed by a droplet discharge method over an area which is pretreated; acolumnar conductive film formed by a droplet discharge method over adrain electrode of the thin film transistor; and a pixel electrodeconnected to the columnar conductive film.

In the above structure, the gate electrode, the drain electrode, or thecolumnar conductive film contains one selected from the group consistingof gold, silver, copper, platinum, palladium, tungsten, nickel,tantalum, bismuth, lead, indium, tin, zinc, titanium, and aluminum.

In each of the above structures, the thin film transistor includes anamorphous semiconductor or a semiamorphous semiconductor.

As to a television receiver disclosed in this specification of theinvention, the liquid crystal display device according to any one ofclaims 1 through 3 is included in a display screen.

Further, a method for manufacturing a liquid crystal display device,disclosed in this specification of the invention includes the steps of:forming a gate electrode over an area which is pretreated by a dropletdischarge method; forming a first insulating film over the gateelectrode; forming a semiconductor film over the first insulating film;forming a mask over the semiconductor film; patterning the semiconductorfilm using the mask; pretreating the patterned semiconductor film;forming a thin film transistor over the pretreated semiconductor film byforming a source or drain electrode by a droplet discharge method;forming a columnar conductive film, over the source or drain electrode;forming a second insulating film so as to cover the columnar conductivefilm and the thin film transistor; forming a pixel electrode so as to beconnected to the columnar conductive film over the second insulatingfilm; forming a liquid crystal or a sealant by a droplet dischargemethod; and pasting with a counter substrate under reduced pressure.

As another method for manufacturing a liquid crystal display device,disclosed in this specification of the invention includes the steps of:forming a gate electrode by a droplet discharge method over an areawhich is pretreated; forming a first insulating film over the gateelectrode; forming a semiconductor film over the first insulating film;forming a mask over the semiconductor film; patterning the semiconductorfilm using the mask; pretreating the patterned semiconductor film;forming a thin film transistor over the pretreated semiconductor film byforming a source or drain electrode by a droplet discharge method;forming a columnar organic film over the source or the drain electrode;forming a second insulating film so as to cover the columnar organicfilm and the thin film transistor; removing the columnar organic film;

forming a pixel electrode so as to be connected to the source or drainelectrode over the second insulating film; forming a liquid crystal or asealant by a droplet discharge method; and pasting with a countersubstrate under reduced pressure.

In the above structures, the second insulating film is repellent to thecolumnar organic film. Further in the above structures, the columnarorganic film is removed by water washing.

The invention can be applied irrespective of the TFT structure. Forexample, the invention can be applied to a top gate TFT, a bottom gate(inverted staggered) TFT, and a staggered TFT. Further, withoutlimitation to a single gate TFT, a multigate TFT which includes pluralchannel regions, for example, a double gate TFT may be used.

As an active layer of the TFT, an amorphous semiconductor film, asemiconductor film containing a crystal structure, a semiconductorcompound film containing an amorphous structure can be appropriatelyused. Further, a semi-amorphous semiconductor film which issemiconductor having an intermediate structure of an amorphous structureand a crystal structure (including single crystal and polycrystal), anda tertiary state which is stable energetically, and including acrystalline region having a short distance order and lattice distortion(also referred to as a microcrystal semiconductor film) can be used asthe active layer of the TFT. In the semi-amorphous semiconductor film, acrystal grain having a grain diameter from 0.5 nm to 20 nm is includedin at least one region of the film, and in the Raman spectrum, the peakspecific to silicon shifts to the lower side of wave number of 520 cm⁻¹.In addition, in the semi-amorphous semiconductor film, a diffractionpeak of (111) and (220) derived from a Si crystal lattice is observed inx-ray diffraction. The semi-amorphous semiconductor film includeshydrogen or halogen at least 1 atom % as a neutralizer of an uncombinedhand (a dangling bond). The semi-amorphous semiconductor film ismanufactured by performing glow discharging decomposition (plasma CVD)of a silicide gas. As the silicide gas, SiH₄, additionally, Si₂H₆,SiH₂Cl₂, SiHCl₃, SiCl₄, SiF₄, or the like can be used. The silicide gasmay be diluted with H₂, or H₂ and one or more of rare gas elements: He,Ar, Kr, and Ne. Dilution ratio is within the range from 2 times to 1000times. Pressure is roughly within the range from 0.1 Pa to 133 Pa; powerfrequency, from 1 MHz to 120 MHz, preferably from 13 MHz to 60 MH; andsubstrate heating temperature, at most 300° C., preferably from 100° C.to 250° C. An atmospheric constitution impurity such as oxygen,nitrogen, or carbon as an impurity element within a film is preferablyat most 1×10²⁰ atoms/cm³, in particular, oxygen concentration is at most5×10¹⁹ atoms/cm³, preferably, at most 1×10¹⁹ atoms/cm³. Note thatelectric field-effect mobility μ of a TFT in using a semi-amorphous filmas an active layer is from 1 cm²/Vsec to 10 cm²/Vsec.

According to the invention, a material layer can be patterned withoutusing a photo mask; thus, the material efficiency can be improved.Further, the manufacturing process can be simplified by skipping thesteps of exposure and development in manufacturing a liquid crystaldisplay device.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1E are figures showing Embodiment Mode 1.

FIGS. 2A to 2E are figures showing Embodiment Mode 2.

FIGS. 3A to 3D are figures showing Embodiment Mode 3.

FIGS. 4A to 4E are figures showing manufacturing steps according toEmbodiment 1.

FIG. 5 is a cross-sectional view showing a liquid crystal display deviceaccording to Embodiment 2.

FIG. 6 is a cross-sectional view showing a liquid crystal display deviceaccording to Embodiment 3.

FIG. 7 is a cross-sectional view showing a liquid crystal display deviceaccording to Embodiment 4.

FIG. 8 is a cross-sectional view showing a liquid crystal display deviceaccording to Embodiment 5.

FIG. 9 is a cross-sectional view showing a liquid crystal display deviceaccording to Embodiment 6.

FIG. 10 is a top view of pixels according to Embodiment Mode 1.

FIGS. 11A to 11D show a perspective view and cross-sectional viewsshowing liquid crystal application by a droplet discharge method.(Embodiment 7)

FIGS. 12A to 12D are top views showing a process. (Embodiment 7)

FIGS. 13A and 13B show cross-sectional views each showing a pastingdevice and a pasting process. (Embodiment 7).

FIGS. 14A and 14B each shows a top view of a liquid crystal module.(Embodiment 7)

FIG. 15 is a cross-sectional view showing an active matrix liquidcrystal display device. (Embodiment 7)

FIGS. 16A to 16C show a droplet discharge system. (Embodiment 8)

FIG. 17 is a figure showing a droplet discharge system. (Embodiment 8)

FIG. 18 is a figure showing a droplet discharge system. (Embodiment 8)

FIGS. 19A and 19B are cross-sectional views of metal particles.(Embodiment 9)

FIGS. 20A to 20C each show a plating machine. (Embodiment 10)

FIGS. 21A to 21C are figures showing examples of electronic devices.(Embodiment 11)

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment modes of the present invention will be described below.

Embodiment Mode 1

Here, a method for manufacturing an active matrix liquid crystal displaydevice using an inverted staggered TFT as a switching element will bedescribed. FIG. 1 shows a cross section of the manufacturing process.

First, a base film 11 for improving adhesion with a material layer to belater formed by a droplet discharge method is formed over a substrate10. The base film 11 may be formed thin; accordingly, it can be regardedas base pretreatment. A photocatalyst (titanium oxide (TiO₂), strontiumtitanate (SrTiO₃), cadmium selenide (CdSe), potassium tantalate (KTaO₃),cadmium sulfide (CdS), zirconium oxide (ZrO₂), niobium oxide (Nb₂O₅),zinc oxide (ZnO), iron oxide (Fe₂O₃), tungsten oxide (WO₃)) may beapplied with a spray; alternatively, an organic material (polyimide,acryl, or a material having a skeletal structure including a bond ofsilicon (Si) and oxygen (O) which contains at least one of the groupconsisting of hydrogen, fluorine, alkyl group and aromatic hydrocarbonas a substituent) may be selectively applied by ink-jet method orsol-gel process.

A photocatalyst denotes a material which has a photocatalytic function.The photocatalyst is activated when it is irradiated with light of anultraviolet light region (wavelength: equal to or less than 400 nm,preferably, equal to or less than 380 nm). A fine pattern can be made bydischarging a conductor contained in a solvent on the photocatalyst byink-jet method.

For example, TiO_(x) is not hydrophilic but oleophilic, that is, waterrepellent before being irradiated with light. Light irradiation causesphotocatalytic activity, and TiO₂ is converted into hydrophilic andnon-oleophilic, that is, oil repellent. Note that TiO₂ can have bothhydrophilic and oleophilic depending on a length of irradiation time.

Note that “hydrophilic” means a state which is easy to be got wet withwater and has a contact angle of equal to or less than 30°.Specifically, a state having a contact angle of equal to or less than 5°is referred to as “super-hydrophilic”. On the other hand,“water-repellent” means a state which is hard to be got wet with waterand has a contact angle of equal to or more than 90°. Similarly,“oleophilic” means a state which is easy to be got wet with oil, and“oil-repellent” means a state which is hard to be got wet with oil. Notethat the contact angle means an angle made by a formation face and atangent to a droplet on the edge of a dropped dot.

Namely, a region irradiated with light (hereinafter, referred to as anirradiation region) becomes hydrophilic or super-hydrophilic (simplycollectively referred to as hydrophilic). At this time, lightirradiation is performed so that a width of an irradiation region is adesired width of a wiring. Thereafter, a dot including a conductivematerial mixed into a water-based solvent is discharged from above theirradiation region to the irradiation region by an ink-jet method. Then,a smaller wiring in width, that is, a narrower wiring than a diameter ofa dot discharged merely by an ink-jet method can be formed. This isbecause the irradiation region is formed to have a desired width of awiring, and then, a discharged dot can be prevented from spreading on aformation surface. Further, a wiring can be formed along the irradiationregion even in the case where a dot is discharged out of alignment tosome extent. Thus, a position of a wiring to be formed can be controlledwith accuracy.

In the case of using a water-based solvent, it is preferable to add asurfactant in order to smoothly discharge a droplet from a nozzle of aninkjet apparatus.

In the case of discharging a conductive material mixed into an oil(alcohol) based solvent, a wiring can be similarly formed by discharginga conductive material onto a region which is not irradiated with light(hereinafter, referred to as a non-irradiation region) and discharging adot from above the non-irradiation region to the non-irradiation region.Namely, opposite ends of a region where a wiring is to be formed, thatis, the periphery surrounding the region where a wiring is to be formedmay be irradiated with light, thereby forming an irradiation region.Since the irradiation region is oil-repellent at this time, a dotincluding a conductive material mixed into an oil (alcohol) basedsolvent is selectively formed in the non-irradiation region. Namely,light irradiation is performed so that a width of the non-irradiationregion is a desired width of a wiring.

Note that a nonpolar solvent or a low polar solvent can be used as theoil (alcohol) based solvent. For example, terpineol, mineral spirit,xylene, toluene, ethyl benzene, mesitylene, hexane, heptane, octane,decane, dodecane, cyclohexane, or cyclooctane can be used.

Further, photocatalytic activity can be improved by doping a transitionmetal (such as Pd, Pt, Cr, Ni, V, Mn, Fe, Ce, Mo, or W) into thephotocatalytic substance, and photocatalytic activity can be caused bylight of a visible light region (wavelength: from 400 nm to 800 nm).This is because the transition metal can form a new level within aforbidden band of an active photocatalyst having a wide band gap and canexpand a light absorption range to a visible light region. For example,an acceptor type such as Cr or Ni, a donor type such as V or Mn, anamphoteric type such as Fe, or other types such as Ce, Mo, and W can bedoped. A wavelength of light can thus be determined depending on thephotocatalytic substance. Therefore, light irradiation means toirradiate with light having such a wavelength that photocatalyticallyactivates the photocatalytic substance.

When the photocatalytic substance is heated and reduced in a vacuum orunder reflux of hydrogen, an oxygen defect is generated in crystal.Without doping a transition element, an oxygen defect plays a similarrole to an electron donor in this way. Specifically, in the case offorming by a sol-gel method, the photocatalytic substance may not bereduced since an oxygen defect exists from the beginning. In addition,an oxygen defect can be formed by doping a gas of N₂ or the like.

Here, an example of carrying out base pretreatment for improving theadhesion in the case of discharging a conductive material onto thesubstrate has been shown. Alternatively, in the case of forming amaterial layer (for example, an organic layer, an inorganic layer, and ametal layer) by a droplet discharge method over another material layer(for example, an organic layer, an inorganic layer, and a metal layer)or a conductive layer formed by discharging, a TiOx film may be formedto improve the adhesion between the material layers. Thus, in the caseof making patterns by discharging a conductive material by a dropletdischarge method, it is desirable to perform base pretreatment beforeand after the formation of the conductive material layer in order toimprove the adhesion.

The substrate 10 may use a plastic substrate having the heat resistancethat can withstand processing temperature or the like other than anon-alkaline glass substrate such as barium borosilicate glass, aluminoborosilicate glass, or aluminosilicate glass manufactured with a fusionmethod or a floating method. Further, a semiconductor substrate of suchas single crystal silicon, a metal substrate of such as stainless steel,a ceramic substrate, or the like whose substrate is provided with aninsulating layer may be applied in the case of a reflective liquidcrystal display device.

Next, after the conductive material is applied by a droplet dischargemethod typified by ink-jet method, baking is carried out in an oxygenatmosphere, thereby forming a metal wiring 12 to be a gate electrode ora gate wiring. Further, a wiring 40 extending to a terminal area is alsoformed similarly. Although not shown, a capacitor electrode or acapacitor wiring for forming a storage capacitor is also formed.

As the wiring material, any one of gold (Au), silver (Ag), copper (Cu),platinum (Pt), palladium (Pd), tungsten (W), nickel (Ni), tantalum (Ta),bismuth (Bi), lead (Pb), indium (In), tin (Sn), zinc (Zn), titanium(Ti), and aluminum (Al); an alloy thereof; dispersed nanoparticlesthereof; or silver halide particles is used. In particular, the gatewiring is preferable to be low resistance. Therefore, a material inwhich any one of gold, silver, or copper dissolved or dispersed in asolvent is preferably used, and more preferably silver or copper withlow resistance is used in consideration of a specific resistance value.However, in the case of using silver or copper, a barrier film may beadditionally provided for an impurity measure. A solvent corresponds toester such as butyl acetate, alcohols such as isopropyl alcohol, anorganic solvent such as acetone, or the like. Surface tension andviscosity are appropriately adjusted by adjusting density of a solventand adding a surfactant or the like.

A diameter of a nozzle used in a droplet discharge method is set to befrom 0.02 μm to 100 μm (preferably, 30 μm or less), and a dischargingamount of a composition discharged from the nozzle is preferably set tobe from 0.001 pl to 100 pl (preferably, 10 pl or less). There are twotypes of an on-demand type and a continuous type for a droplet dischargemethod, both of which may be used. Furthermore, there is a piezoelectricsystem using properties transformed by applying voltage pressure of apiezoelectric material and a heating system that boils a composition bya heater provided in a nozzle and discharges the composition for anozzle to be used in a droplet discharge method, both of which may beused. A distance between a subject and a discharge opening of a nozzleis preferable to be made as close as possible to drop a droplet at adesired place, which is preferably set to be from 0.1 mm to 3 mm(preferably, 1 mm or less). While keeping the relative distance, one ofthe nozzle and the subject moves and a desired pattern is drawn. Inaddition, plasma treatment may be carried out on a surface of thesubject before discharging a composition. This is to take advantage of asurface of the subject becoming hydrophilic and lyophobic when plasmatreatment is carried out. For example, it becomes hydrophilic todeionized water and it becomes lyophobic to a paste dissolved withalcohol.

A step of discharging a composition may be carried out under lowpressure so that a solvent of the composition can be volatilized whilethe composition is discharged and hit on a subject and later steps ofdrying and baking can be skipped or shorten. After discharging acomposition, either or both steps of drying and baking is carried out byirradiation of laser light, rapid thermal annealing, heating furnace, orthe like under the atmospheric pressure or the low pressure. Both thesteps of drying and baking are steps of heat treatment. For example,drying is carried out at 100° C. for 3 minutes and baking is carried outat temperatures from 200° C. to 350° C. for from 15 minutes to 120minutes. In order to carry out the steps of drying and baking well, asubstrate may be heated, of which temperatures are set to be from 100°C. to 800° C. (preferably, temperatures from 200° C. to 350° C.), thoughdepending on a material of a substrate or the like. Through this step, asolvent in a composition is volatilized or dispersant is removedchemically, and a resin around cures and shrink, thereby acceleratingfusion and welding. It is carried out under the oxygen atmosphere, thenitrogen atmosphere, or the atmosphere. However, this step is preferableto be carried out under an oxygen atmosphere in which a solventdecomposing or dispersing a metal element is easily removed.

The adhesion of a metal film which is later to be formed by a dropletdischarge method can be significantly improved by forming the base filmor by carrying out base pretreatment. Thus, the adhesion which canresist even soaked in dilute hydrofluoric acid (diluted 1:100) for oneminute or more, and can resist tape adhesion test can be obtained.

Next, a gate insulating film 13 is formed by plasma CVD, sputtering, orcoating to have a single layer structure or a layered structure.Desirably, a stack of three layers of an insulating layer formed ofsilicon nitride, an insulating layer formed of silicon oxide, and aninsulating layer formed of silicon nitride. Alternatively, a stack oftwo layers of an insulating layer formed of silicon nitride and aninsulating layer formed of polyimide. Note that a rare gas element suchas argon is preferably contained in a reactive gas, which is mixed intothe insulating film to be formed.

A semiconductor film 14 a is formed. The semiconductor film 14 a isformed with an amorphous semiconductor film or a semiamorphoussemiconductor film which is formed by vapor phase growth or sputteringusing a semiconductor material gas typified by silane and germanium.

As an amorphous semiconductor film, an amorphous silicon film obtainedby PCVD using SiH₄ or a gas mixture of SiH₄ and H₂. Further, as asemiamorphous semiconductor film, a semiconductor film obtained by PCVDusing a gas mixture in which SiH₄ is diluted 1:3 to 1:1000 in H₂, a gasmixture in which Si₂H₆ is diluted with GeF₄ with a gas flow rate of20:0.9 to 40:0.9 (Si₂H₆:GeF₄), or a gas mixture of SiH₄ and H₂. Notethat a semiamorphous silicon film is preferably used since morecrystallinity can be given to the interface with the base.

An insulating layer 16 is formed by plasma CVD or sputtering. Thepatterning may be performed by etching with the use of a mask formed bya droplet discharge method, or photolithography. The insulating layer 16is made to remain on the semiconductor layer opposite to the gateelectrode so as to serve as a channel protective layer. Further, theinsulating layer 16 is preferably formed with a fine film therebyacquiring purity of the surface and preventing the semiconductor layerfrom being contaminated by impurities such as an organic material, ametal material, or moisture. In a glow discharge decomposition method, asilicon nitride film which is formed by diluting a silicide gas by from100 times to 500 times with a silicide gas such as argon is preferablesince a fine film can be formed even at a deposition temperature of 100°C. or less.

Subsequently, a mask 15 covering the insulating layer 16 is formed by adroplet discharge method (FIG. 1A). A resin material such as an epoxyresin, an acrylic resin, a phenol resin, a novolac resin, a melamineresin, or a urethane resin is used for the mask 15. In addition, themask 213 is formed with a droplet discharge method by using an organicmaterial such as benzocyclobutene, parylene, flare, orlight-transmitting polyimide; a compound material made frompolymerization such as siloxane-based polymer; a composition materialcontaining water-soluble homopolymer and water-soluble copolymer; or thelike. Alternatively, a commercial resist material containing aphotosensitizer may be used. For example, a typical positive type resistsuch as a novolac resin and naphthoquinonedi azide compound that is aphotosensitizer, a negative type resist such as a base resin,diphenylsilane diol, and an acid generation agent, or the like may beused. In using any one of materials, surface tension and viscosity areappropriately controlled by diluting the concentration of a solvent oradding a surfactant or the like.

Next, a semiconductor film 14 a except the area covered with the mask 15is removed by dry etching or wet etching, so that a semiconductor layer14 b to be an active layer is formed.

After the mask 15 is removed, an n-type semiconductor film 17 is formedover the entire surface. In the case where the n-type semiconductor filmis provided, the contact resistance between the semiconductor film andthe electrode is reduced, which is preferable. The n-type semiconductorfilm may be provided as necessary. The n-type semiconductor film 17 maybe formed with an amorphous semiconductor film or a semiamorphoussemiconductor film formed by PCVD using silane gas and phosphine gas.

Next, a composition containing a conductive material (such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum)) isselectively discharged, so that source and drain wirings 18 a and 18 bare formed. A connection wiring 41 is similarly formed in a terminalarea (FIG. 1B).

The n-type semiconductor film 17 is etched in a self-aligned manner byusing the source and drain wirings 18 a and 18 b as masks therebyforming source and drain regions 19 a and 19 b. Thus, a channel stop TFT30 is completed. The insulating layer 16 is used as an etching stopperof the n-type semiconductor film

Next, the area except the terminal area is covered with a resin such asa resist by using a shadow mask. In the terminal area, a part of awiring 40 is exposed by etching a gate insulating film 13 using theconnection wiring 41 as a mask. A resist mask formed by screen printingmay be used as an etching mask instead of the shadow mask. In addition,the gate insulating film 13 may be etched without covering the areaexcept the terminal area with a resist. However, there are problems thatthe gate insulating film of the area which is not overlapped with thesource and drain wirings 18 a and 18 b is etched, and that thesemiconductor layer would be exposed since the insulating layer 16 isetched.

Next, a conductor 42 for connecting the wiring 40 extending to theterminal area and the connection wiring 41 is formed. The conductor 42may be formed by printing or by a droplet discharge method. In the caseof using a droplet discharge method, a composition containing aconductive material (such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum)) is selectively discharged to form theconductor 42.

A projection (pillar) 20 formed of a conductive material is formed overa part of the source or drain wiring 18 a. A stack is formed byrepeating discharging and baking of a composition containing aconductive material (such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum)), so that the projection (pillar) 20 isformed. A projection (pillar) 43 is also formed over the connectionwiring 41 in a similar manner. Alternatively, the projections (pillars)20 and 43 may be formed by patterning a metal film formed by sputtering.In this case, the projection (pillar) is shaped like a column.

A interlayer insulating film 21 which is flat is formed by coating (FIG.1C). The interlayer insulating film 21 which is flat and formed bycoating denotes an interlayer insulating film formed by applying aliquid composition. For the interlayer insulating film 21 which is flatformed by coating, an organic material such as acrylic or polyimide; orspin on glass (hereinafter also referred to as SOG) that is a coatingwhich is formed by application of an insulating material dissolved in anorganic solvent and by heat treatment thereafter, for example, amaterial in which a siloxane bond is formed by baking siloxane polymeror the like may be used. The interlayer insulating film 21 may be formedwith an inorganic insulating film such as a silicon oxide film formed bya vapor phase growth method or sputtering instead of coating. Further,after a silicon nitride film is formed as a protective film by PCVD orsputtering, the interlayer insulating film 21 may be formed by coating.

The interlayer insulating film 21 may be formed by a droplet dischargemethod. Further, the interlayer insulating film 21 may be formed by adroplet discharge method before final bake of the projections (pillars)20 and 43; thus, the final bake thereof is carried out simultaneously.

In forming the interlayer insulating film 21 which is flat by coating ora droplet discharge method, it is preferable to carry out final bakeafter minute irregularities on the surface are planarized with an airknife instead of a squeegee.

Parts of the interlayer insulating film over the projections (pillars)20 and 43 are removed by etch back of the entire surface, so that theprojections (pillars) 20 and 43 are exposed. Alternatively, theinterlayer insulating film may be grinded by chemical mechanicalpolishing (CMP) and thereafter carrying out etch back of the entiresurface; thus, the projections (pillars) 20 and 43 can be exposed.

A pixel electrode 23 in contact with the projection (pillar) 20 isformed over an interlayer insulating film 22 (FIG. 1D). A terminalelectrode 44 in contact with the projection (pillar) 43 is similarlyformed. In the case of manufacturing a transmissive liquid crystaldisplay panel, a pattern formed of a composition containing indium tinoxide (ITO), indium tin oxide containing silicon oxide (ITSO), zincoxide (ZnO), tin oxide (SnO₂), or the like may be formed by a dropletdischarge method or printing, and baked to form the pixel electrode 23and the terminal electrode 44. In the case of manufacturing a reflectiveliquid crystal display panel, the pixel electrode 23 and the terminalelectrode 44 can be formed of a composition mainly containing particlesof a metal such as Ag (silver), Au (gold), Cu (copper), W (tungsten), orAl (aluminum) by a droplet discharge method. As another method, atransparent conductive film or a light reflective conductive film isformed by sputtering, and a mask pattern is formed by a dropletdischarge method; thus, the pixel electrode may be formed by a pluralityof etching methods. Note that the surface of the interlayer insulatingfilm 22 is planarized by etch back or CMP, so that a flat pixelelectrode 23 can be formed.

FIG. 10 is an enlarged top view of a part of a pixel area. Further, FIG.10 shows a pixel electrode in the course of being formed; a pixelelectrode is formed in the left pixel whereas a pixel electrode is notyet provided in the right pixel. A cross-sectional view taken along thesolid line A-A′ in FIG. 10 corresponds to the cross section of the pixelarea shown in FIG. 1D; accordingly, the same reference numerals are usedfor the corresponding parts. The pixel area is provided with a capacitorwiring 31, a storage capacitor using a gate insulating film as adielectric, a pixel electrode 23, and the capacitor wiring 31overlapping the pixel electrode.

Through the above steps, a TFT substrate for a liquid crystal displaypanel in which a bottom gate (inverted staggered) TFT and a pixelelectrode are formed over a substrate 10 is completed.

Next, an alignment layer 24 a is formed so as to cover the pixelelectrode 23. The alignment layer 24 a may be formed by a dropletdischarge method, screen printing, or off-set printing. Subsequently,the surface of the alignment layer 24 a is rubbed.

A counter substrate 25 is provided with a color filter formed with acolor layer 26 a, a light shielding layer (black matrix) 26 b, and anover coat layer 27; a counter electrode 28 formed with a transparentelectrode; and the alignment layer 24 b thereover. Here, a sealant witha closed pattern (not shown) is used since liquid crystal 29 is dropped.Alternatively, dip coating (pumping up method) by which liquid crystal29 is injected by capillary phenomenon after pasting the TFT substrateand a counter substrate may be employed using a seal pattern having anopening.

Next, liquid crystal 29 is dropped under reduced pressure so as toprevent bubbles from entering, and the TFT substrate and the countersubstrate are pasted together. Liquid crystal 29 is dropped once orseveral times in the closed seal pattern. A twisted nematic (TN) mode ismostly employed as an alignment mode of a liquid crystal. In this mode,the alignment direction of liquid crystal molecules is twisted at 90°according to the polarization of light from its entrance to the exit. Inthe case of manufacturing a TN liquid crystal display device, analignment layer is formed on both of the substrates; the substrates arepasted together so that the rubbing directions of the substrates areorthogonalized.

The gap between the pair of the substrates may be maintained by sprayingspherical spacers, forming a column spacer formed of resin, or mixingfillers into the sealant. The columnar spacer is formed of an organicresin material containing as a main component at least one materialselected from the group consisting of acrylic, polyimide,polyimideamide, and epoxy; any one material of silicon oxide, siliconnitride, and silicon oxynitride; or an inorganic material composed of astack of these materials.

Next, unnecessary substrate is divided. In the case of obtaining aplurality of panels from one substrate, each panel is separated off. Inthe case of obtaining one panel from one substrate, the separation stepcan be skipped by pasting a counter substrate which is previously cut.

An FPC 46 is bonded to the TFT substrate with an anisotropic conductivelayer 45 therebetween by a known method. A liquid crystal module iscompleted through the above steps (FIG. 1E). Further, an optical film isprovided as necessary. In the case of a transmissive liquid crystaldisplay device, polarizers are respectively pasted to both an activematrix substrate and a counter substrate.

As described above, according to this embodiment mode, the lightexposure using a photomask is skipped by using the projections (pillars)20 and 43; thus, the process can be simplified and the time ofmanufacture can be reduced. A liquid crystal display device can beeasily manufactured by even using a glass substrate after fivegenerations, one side of which exceeds 1000 mm by forming each kind ofpattern directly on a substrate by using a droplet discharge method.

In this embodiment mode, a process in which a light exposure processusing a photomask is not carried out; however, a part of patterning maybe performed by light exposure using a photomask.

Embodiment Mode 2

Here, an example in which the connection method is different fromEmbodiment Mode 1 will be shown. FIG. 2A to 2E show a cross section ofmanufacturing steps of an active matrix liquid crystal display deviceusing an inverted staggered TFT as a switching element.

First, a state equivalent to FIG. 1A is made according to the stepsshown in Embodiment Mode 1. A base: film 211, a metal wiring 212, awiring 240 extending to a terminal area are formed over a substrate 210.Further, a gate insulating film 213, a semiconductor film 214 a, and aninsulating layer 216 are sequentially formed thereover. A mask 215covering the insulating layer 216 is formed by a droplet dischargemethod (FIG. 2A).

Next, a semiconductor film 214 a except the area covered with the mask215 is removed by dry etching or wet etching, so that a semiconductorlayer 214 b to be an active layer is formed.

After the mask 215 is removed, an n-type semiconductor film 217 isformed over the entire surface. The n-type semiconductor film 217 may beprovided as necessary. The n-type semiconductor film 217 may be formedwith an amorphous semiconductor film or a semiamorphous semiconductorfilm formed by PCVD using phosphine gas

Next, a composition containing a conductive material (such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum)) isselectively discharged, so that source and drain wirings 218 a and 218 bare formed. A connection wiring 241 is similarly formed in a terminalarea (FIG. 2B). Since the drain wiring 218 b serves as a pixel electrode(reflective electrode), it is preferable to use Ag (silver), Al(aluminum), or the like, which is highly reflective. Since the pixelelectrode is formed by a droplet discharge method, irregularities forpreventing mirror surface reflection of the reflective electrode can beeasily formed. Conventionally, after the pixel electrode is formed, thesurface is provided with irregularities by adding the steps of sandblasting, etching, or the like to prevent mirror reflection and to allowreflected light to scatter, thereby enhancing whiteness.

The n-type semiconductor film 217 is etched in a self-aligned manner byusing the source and drain wirings 218 a and 218 b as masks therebyforming source and drain regions 219 a and 219 b. Thus, a channel stopTFT 230 is completed. The insulating layer 216 is used as an etchingstopper of the n-type semiconductor film 217.

Next, the area except the terminal area is covered with a resin such asa resist by using a shadow mask. In the terminal area, a part of awiring 240 is exposed by etching a gate insulating film 213 using theconnection wiring 241 as a mask.

Next, a conductor 242 for connecting the wiring 240 extending to theterminal area and the connection wiring 241 is formed. The conductor 242may be formed by printing or by a droplet discharge method. In the caseof using a droplet discharge method, a composition containing aconductive material (such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum)) is selectively discharged to form theconductor 242.

Next, an interlayer insulating film 221 is selectively formed by adroplet discharge method (FIG. 2C). In the pixel area, the interlayerinsulating film is formed so as to cover the area except the part laterto be a pixel electrode. Droplet discharge and bake may be repeated twoor more times to make the interlayer insulating film thick enough. Inthe terminal area, the interlayer insulating film 221 is provided so asnot to cover the part later to be a terminal electrode. Thus, theinterlayer insulating film is not provided in the areas where connectionis made or the insulating film is not required. Accordingly, theformation of contact holes is redundant.

The interlayer insulating film 221 can be formed of an insulatingmaterial which can be applied by a droplet discharge method; forexample, a photosensitive or non-photosensitive organic material(polyimide, acrylic, polyamide, polyimide amide, benzocyclobutene, or aresist material), siloxane, polysilazane, or a layered structuredthereof can be used. Siloxane is formed with a polymer material with askeletal structure having a bond of silicon (Si) and oxygen (O) whichcontains at least hydrogen as a substituent, or contains at least one offluorine, alkyl group, and aromatic hydrocarbon. Polysilazane is formedwith a liquid material, that is, a polymer material having a bond ofsilicon (Si) and nitrogen (N).

Next, a terminal electrode 244 in contact with a connection wiring 241is formed by a droplet discharge method or printing (FIG. 2D). Acomposition containing indium tin oxide (ITO), indium tin oxidecontaining silicon oxide (ITSO), zinc oxide (ZnO), tin oxide (SnO₂), orthe like is used for the terminal electrode 244.

Note that, the terminal electrode 244 may be formed before the formationof the interlayer insulating film 221; or may be formed concurrentlywith the interlayer insulating film 221 by using a head by whichdifferent materials are discharged simultaneously. Further, only thebaking steps of the terminal electrode 244 and the interlayer insulatingfilm 221 may be performed in common.

Through the above steps, a TFT substrate for a reflective liquid crystaldisplay panel in which a bottom gate (inverted staggered) TFT and apixel electrode are formed over a substrate 210 is completed.

Next, an alignment layer 224 a is formed so as to cover the pixelelectrode 218 a. The alignment layer 224 a may be formed by a dropletdischarge method, screen printing, or off-set printing. Subsequently,the surface of the alignment layer 224 a is rubbed.

A counter substrate 225 is provided with a color filter formed with acolor layer 226 a, a light shielding layer (black matrix) 226 b, and anover coat layer 227; a counter electrode 228 formed with a transparentelectrode; and the alignment layer 224 b thereover. Here, a sealant witha closed pattern (not shown) is used since liquid crystal 229 isdropped. Alternatively, dip coating (pumping up method) by which liquidcrystal 229 is injected by capillary phenomenon after pasting the TFTsubstrate and a counter substrate may be employed using a seal patternhaving an opening.

Next, liquid crystal 229 is dropped under reduced pressure so as toprevent bubbles from entering, and the TFT substrate and the countersubstrate are pasted together. Liquid crystal 229 is dropped once orseveral times in the closed seal pattern. A twisted nematic (TN) mode ismostly employed as an alignment mode of a liquid crystal. In this mode,the alignment direction of liquid crystal molecules is twisted at 90°according to the polarization of light from its entrance to the exit. Inthe case of manufacturing a TN liquid crystal display device, analignment layer is formed on both of the substrates; the substrates arepasted together so that the rubbing directions of the substrates areorthogonalized.

The gap between the pair of the substrates may be maintained by sprayingspherical spacers, forming a column spacer formed of resin, or mixingfillers into the sealant. The columnar spacer is formed of an organicresin material containing as a main component at least one materialselected from the group consisting of acrylic, polyimide,polyimideamide, and epoxy; any one material of silicon oxide, siliconnitride, and silicon oxynitride; or an inorganic material composed of astack of these materials.

Next, unnecessary substrate is divided. In the case of obtaining aplurality of panels from one substrate, each panel is separated off. Inthe case of obtaining one panel from one substrate, the separation stepcan be skipped by pasting a counter substrate which is previously cut.

An FPC 246 is bonded to the TFT substrate with an anisotropic conductivelayer 245 therebetween by a known method. A liquid crystal module iscompleted through the above steps (FIG. 2E). Further, an optical film isprovided as necessary. In the case of a transmissive liquid crystaldisplay device, polarizers are respectively pasted to both an activematrix substrate and a counter substrate.

As described above, according to this embodiment mode, the lightexposure using a photomask is skipped by selectively forming aninterlayer insulating film by a droplet discharge method; thus, theprocess can be simplified and the time of manufacture can be reduced. Aliquid crystal display device can be easily manufactured by even using aglass substrate after five generations, one side of which exceeds 1000mm by forming each kind of pattern directly on a substrate by using adroplet discharge method.

In this embodiment mode, a process in which a light exposure processusing a photomask is not carried out; however, a part of patterning maybe performed by light exposure using a photomask.

Embodiment Mode 3

Here, an example in which the connection method is different fromEmbodiment Mode 1 will be shown. FIG. 3A to 3D show a cross section ofmanufacturing steps of an active matrix liquid crystal display deviceusing an inverted staggered TFT as a switching element.

First, a state equivalent to FIG. 1C is made according to the stepsshown in Embodiment Mode 1. A base film 311, a metal wiring 312, awiring 340 extending to a terminal area are formed over a substrate 310.Further, a gate insulating film 313, a semiconductor film, and aninsulating layer 316 are sequentially formed thereover. A mask coveringthe insulating layer 316 is formed by a droplet discharge method. Next,a semiconductor film except the area covered with the mask is removed bydry etching or wet etching, so that a semiconductor layer 314 to be anactive layer is formed. After the mask is removed, an n-typesemiconductor film is formed over the entire surface. Next, acomposition containing a conductive material (such as Ag (silver), Au(gold), Cu (copper), W (tungsten), or Al (aluminum)) is selectivelydischarged, so that source and drain wirings 318 a and 318 b, and aconnection wiring 341 are formed. The n-type semiconductor film isetched in a self-aligned manner by using the source and drain wirings318 a and 318 b as masks thereby forming source and drain regions 319 aand 319 b. Thus, a channel stop TFT 330 is completed. The insulatinglayer 316 is used as an etching stopper of the n-type semiconductorfilm. Next, the area except the terminal area is covered with a resinsuch as a resist by using a shadow mask. In the terminal area, the gateinsulating film 313 is etched to expose a part of the wiring 340 byusing the connection wiring 341 as a mask. Further, a conductor 342 forconnecting the wiring 340 extending to the terminal area and theconnection wiring 341 is formed.

A projection (pillar) 320 formed of a liquid repellent (water repellent,oil repellent) material is formed over a part of the source or drainwiring 318 a by a droplet discharge method. A stack is formed byrepeating discharging and baking of a composition containing a liquidrepellent material (a fluorine based resin such as fluoroalkyl silane(FAS)), so that the projection (pillar) 320 is formed. Also, aprojection (pillar) 343 is formed on the connecting wiring 341. Theprojections (pillars) 320 and 343 may be formed of a material which isnot liquid repellent, and may be thereafter made liquid repellent by CF₄plasma treatment or the like. For example, after the projections(pillars) are formed of a water soluble resin such as polyvinyl alcohol(PVA), CF₄ plasma treatment may be performed to make the projections(pillars) liquid repellent.

Further, a contact hole can be formed without performing CF₄ plasmatreatment by using a liquid repellent material. After a liquid repellentmaterial (a fluorine based resin such as fluoroalkyl silane (FAS)) isapplied over the entire surface, a mask is formed of a water solubleresin such as polyimide and polyvinyl alcohol (PVA). The liquidrepellent material on the area except where the mask is formed isremoved by O₂ asking or the like, and the mask is removed. Here, onlythe area where the mask is removed is liquid repellent. When aninsulating material is thereafter applied over the entire surface, theinsulating film is not formed over the area where the mask is removed(the area which is liquid repellent). Thus, an insulating film in whichonly the desired area is exposed can be obtained.

Next, a flat interlayer insulating film 322 is formed. A flat film maybe obtained by using a coating method. Alternatively, the interlayerinsulating film 322 may be formed by a droplet discharge method, andminute projections on the surface may be planarized with an air knife.For the flat interlayer insulating film 322, an organic material such asacrylic or polyimide; or spin on glass (hereinafter also referred to asSOG) that is a coating which is formed by application of an insulatingmaterial dissolved in an organic solvent and by heat treatmentthereafter, for example, a material in which a siloxane bond is formedby baking siloxane polymer or the like may be used.

In the case of forming the projections (pillars) 320 and 343 which arerepellent to the solution used for the formation of the interlayerinsulating film, the interlayer insulating film is formed so as not tobe formed on the projections.

Next, contact holes are formed by removing only the projections(pillars) 320 and 343 (FIG. 3B).

A pixel electrode 323 in contact with the drain wiring 318 a is formed(FIG. 3C). Similarly, a terminal electrode 344 in contact with theconnection wiring 341 is formed.

In the case of manufacturing a transmissive liquid crystal displaypanel, a pattern formed of a composition containing indium tin oxide(ITO), indium tin oxide containing silicon oxide (ITSO), zinc oxide(ZnO), tin oxide (SnO₂), or the like may be formed by a dropletdischarge method, and baked to form the pixel electrode 323 and theterminal electrode 344. In the case of manufacturing a reflective liquidcrystal display panel, the pixel electrode 323 and the terminalelectrode 344 can be formed of a composition mainly containing particlesof a metal such as Ag (silver), Au (gold), Cu (copper), W (tungsten), orAl (aluminum). As another method, a transparent conductive film or alight reflective conductive film is formed by sputtering and a maskpattern is formed by a droplet discharge method; thus, the pixelelectrode may be formed by combining etching.

Through the above steps, a TFT substrate for a liquid crystal displaypanel in which a bottom gate (inverted staggered) TFT and a pixelelectrode are formed over a substrate 310 is completed.

Next, an alignment layer 324 a is formed so as to cover the pixelelectrode 323. The alignment layer 324 a may be formed by a dropletdischarge method, screen printing, or off-set printing. Subsequently,the surface of the alignment layer 324 a is rubbed.

A counter substrate 325 is provided with a color filter formed with acolor layer 326 a, a light shielding layer (black matrix) 326 b, and anover coat layer 327; a counter electrode 328 formed with a transparentelectrode; and the alignment layer 324 b thereover. Here, a sealant witha closed pattern (not shown) is used since liquid crystal 329 isdropped. Alternatively, dip coating (pumping up method) by which liquidcrystal 329 is injected by capillary phenomenon after pasting the TFTsubstrate and a counter substrate may be employed using a seal patternhaving an opening.

Next, liquid crystal 329 is dropped under reduced pressure so as toprevent bubbles from entering, and the TFT substrate and the countersubstrate are pasted together. Liquid crystal 329 is dropped once orseveral times in the closed seal pattern. A twisted nematic (TN) mode ismostly employed as an alignment mode of a liquid crystal. In this mode,the alignment direction of liquid crystal molecules is twisted at 90°according to the polarization of light from its entrance to the exit. Inthe case of manufacturing a TN liquid crystal display device, analignment layer is formed on both of the substrates; the substrates arepasted together so that the rubbing directions of the substrates areorthogonalized.

The gap between the pair of the substrates may be maintained by sprayingspherical spacers, forming a column spacer formed of resin, or mixingfillers into the sealant. The columnar spacer is formed of an organicresin material containing as a main component at least one materialselected from the group consisting of acrylic, polyimide,polyimideamide, and epoxy; any one material of silicon oxide, siliconnitride, and silicon oxynitride; or an inorganic material composed of astack of these materials.

Next, unnecessary substrate is divided. In the case of obtaining aplurality of panels from one substrate, each panel is separated off. Inthe case of obtaining one panel from one substrate, the separation stepcan be skipped by pasting a counter substrate which is previously cut.

An FPC 346 is bonded to the TFT substrate with an anisotropic conductivelayer 345 therebetween by a known method. A liquid crystal module iscompleted through the above steps (FIG. 3D). Further, an optical film isprovided as necessary. In the case of a transmissive liquid crystaldisplay device, polarizers are respectively pasted to both an activematrix substrate and a counter substrate.

As described above, according to this embodiment mode, the lightexposure using a photomask is skipped by using a projection (pillar) 343which is liquid repellent; thus, the process can be simplified and thetime of manufacture can be reduced. A liquid crystal display device canbe easily manufactured by even using a glass substrate after fivegenerations, one side of which exceeds 1000 mm by forming each kind ofpattern directly on a substrate by using a droplet discharge method.

In this embodiment mode, a process in which a light exposure processusing a photomask is not carried out; however, a part of patterning maybe performed by light exposure using a photomask.

The invention having the above structure will be described in detailusing the following embodiments.

Embodiment 1

In this embodiment, an example of manufacturing an active matrix liquiddisplay device using a channel etch TFT will be shown: FIGS. 4A to 4Eshow a cross section of manufacturing steps.

First, a base film 411, a metal wiring 412, a wiring 440 extending to aterminal area are formed over a substrate 410 according to the stepsshown in Embodiment Mode 1. Further, a gate insulating film 413 isformed thereover.

A semiconductor film 414 a and an n-type semiconductor film 417 areformed in layers. The semiconductor film 414 a is formed with anamorphous semiconductor film or a semiamorphous semiconductor film whichis formed by vapor phase growth or sputtering using a semiconductormaterial gas typified by silane and germanium. As an amorphoussemiconductor film, an amorphous silicon film obtained by PCVD usingSiH₄ or a gas mixture of SiH₄ and H₂. Further, as a semiamorphoussemiconductor film, a semiconductor film obtained by PCVD using a gasmixture in which SUL is diluted 1:3 to 1:1000 in H₂, a gas mixture inwhich Si₂H₆ is diluted with GeF₄ with a gas flow rate of 20:0.9 to40:0.9 (Si₂H₆:GeF₄), or a gas mixture of SiH₄ and H₂. Note that asemiamorphous silicon film is preferably used since crystallinity can begiven to the interface from the base. The n-type semiconductor film 417may be formed with an amorphous semiconductor film or a semiamorphoussemiconductor film formed by PCVD using silane gas and phosphine gas.Note that, the gate insulating film 413, the semiconductor film 414 a,and the n-type semiconductor film 417 can be formed continuously withoutbeing exposed to the atmosphere. Penetration of impurities can beprevented by avoiding exposure to the atmosphere by PCVD.

Subsequently, a mask 415 for patterning the semiconductor layer isformed by a droplet discharge method (FIG. 4A). A resin material such asan epoxy resin, an acrylic resin, a phenol resin, a novolac resin, amelamine resin, or a urethane resin is used for the mask 415. In usingany one of materials, surface tension and viscosity are appropriatelycontrolled by diluting the concentration of a solvent or adding asurfactant or the like.

Next, a semiconductor film 414 a except the area covered with the mask415 and the n-type semiconductor film 417 are removed by dry etching orwet etching, so that a semiconductor layer to be an active layer isformed.

In order to achieve good coverage, a layer formed of an insulatingmaterial or a conductive material 416 which covers the edge of thesemiconductor layer is formed by a droplet discharge method.

A composition containing a conductive material (such as Ag (silver), Au(gold), Cu (copper), W (tungsten), or Al (aluminum)) is selectivelydischarged by a droplet discharge method to form a source wiring and adrain wiring 418 a and 418 b.

Next, a mask used for removing a part of the semiconductor layer whichis overlapped with the metal wiring 412 serving as a gate electrode withthe gate insulating film 413 therebetween is formed by a dropletdischarge method. N-type semiconductor films 419 a and 419 b are formedby etching concurrently with a semiconductor layer 414 b, a part ofwhich has been overlapped with the metal wiring 412 serving as a gateelectrode and is removed. Thus, a channel etch TFT 430 is completed.

Next, the area except the terminal area is covered with a resin such asa resist by using a shadow mask. In the terminal area, a part of thewiring 440 is exposed by etching a gate insulating film 413 using theconnection wiring 441 as a mask (FIG. 4B). A resist mask formed byscreen printing may be used as an etching mask instead of the shadowmask.

The rest of the steps may be performed in the similar manner asEmbodiment Mode 1. This embodiment has the same structure as EmbodimentMode 1 only except for the TFT structure.

Next, a conductor 442 for connecting the wiring 440 extending to theterminal area and the connection wiring 441 is formed. The conductor 442may be formed by printing or by a droplet discharge method.

A projection (pillar) 420 formed of a conductive material is formed overa part of the source or drain wiring 418 a. A projection (pillar) 443 isalso formed over the connection wiring 441 in a similar manner.

An interlayer insulating film 421 which is flat is formed by coating(FIG. 4C). The interlayer insulating film 421 may be formed with aninorganic insulating film such as a silicon oxide film formed by a vaporphase growth method or sputtering instead of coating. Further, after asilicon nitride film is formed as a protective film by PCVD orsputtering, the interlayer insulating film 421 may be formed by coating.

The interlayer insulating film 421 may be formed by a droplet dischargemethod. Further, the interlayer insulating film 421 may be formed by adroplet discharge method before final bake of the projections (pillars)420 and 443; thus, the final bake thereof is carried out simultaneously.

A part of the interlayer insulating film over the projections (pillars)420 and 443 is removed by etch back of the entire surface, so that theprojections (pillars) 420 and 443 are exposed. Alternatively, theinterlayer insulating film may be grinded by Chemical mechanicalpolishing (CMP) and thereafter carrying out etch back of the entiresurface; thus, the projections (pillars) 420 and 443 can be exposed.

A pixel electrode 423 is formed in contact with the projection (pillar)420 on an interlayer insulating film 422 which is made flat (FIG. 4D).Similarly, the a terminal electrode 444 in contact with the projection(pillar) 443 is formed. In the case of manufacturing a transmissiveliquid crystal display panel, a pattern formed of a compositioncontaining indium tin oxide (ITO), indium tin oxide containing siliconoxide (ITSO), zinc oxide (ZnO), tin oxide (SnO₂), or the like may beformed by a droplet discharge method or screen printing, and baked toform the pixel electrode 423 and the terminal electrode 444. In the caseof manufacturing a reflective liquid crystal display panel, the pixelelectrode 423 and the terminal electrode 444 can be formed of acomposition mainly containing particles of a metal such as Ag (silver),Au (gold), Cu (copper), W (tungsten), or Al (aluminum) by a dropletdischarge method.

Through the above steps, a TFT substrate for a liquid crystal displaypanel in which a bottom gate (inverted staggered) TFT and a pixelelectrode are formed over a substrate 410 is completed.

Next, an alignment layer 424 a is formed so as to cover the pixelelectrode 423. The alignment layer 424 a may be formed by a dropletdischarge method, screen printing, or off-set printing. Subsequently,the surface of the alignment layer 424 a is rubbed.

A counter substrate 425 is provided with a color filter formed with acolor layer 426 a, a light shielding layer (black matrix) 426 b, and anover coat layer 427; a counter electrode 428 formed with a transparentelectrode; and the alignment layer 424 b thereover. In this embodiment,a sealant with a closed pattern (not shown) is used since liquid crystal429 is dropped. Alternatively, dip coating (pumping up method) by whichliquid crystal 429 is injected by capillary phenomenon after pasting theTFT substrate and a counter substrate may be employed using a sealpattern having an opening.

Next, liquid crystal 429 is dropped under reduced pressure so as toprevent bubbles from entering, and the TFT substrate and the countersubstrate are pasted together. Liquid crystal is dropped once or severaltimes in the closed seal pattern.

The gap between the pair of the substrates may be maintained by sprayingspherical spacers, forming a column spacer formed of resin, or mixingfillers into the sealant.

Next, unnecessary substrate is divided. In the case of obtaining aplurality of panels from one substrate, each panel is separated off. Inthe case of obtaining one panel from one substrate, the separation stepcan be skipped by pasting a counter substrate which is previously cut.

An FPC 446 is bonded to the TFT substrate with an anisotropic conductivelayer 445 therebetween by a known method. A liquid crystal module iscompleted through the above steps (FIG. 4E). Further, an optical film isprovided as necessary. In the case of a transmissive liquid crystaldisplay device, polarizers are respectively pasted to both an activematrix substrate and a counter substrate.

In this embodiment, a process in which a light exposure process using aphotomask is not carried out; however, a part of patterning may beperformed by light exposure using a photomask. For example, if aphotomask used in a patterning step of removing a part of thesemiconductor film, by which the size of a channel region is determined,the size can be determined finely.

This embodiment can be freely combined with Embodiment Mode 1.

Embodiment 2

In this embodiment, an example of manufacturing an active matrix liquiddisplay device using a channel etch TFT will be shown. FIG. 5 shows across section of a liquid crystal display device.

Since this embodiment is similar to Embodiment Mode 2 except that theTFT in Embodiment Mode 2 has a channel stop structure. Accordingly, onlysimple explanation will be given here.

Further, a channel etch ITT 530 may be formed through the stepsaccording to Embodiment 1. This embodiment includes similar steps toEmbodiment 1 except for that a part of a pattern of a drain wiringserves as a pixel electrode (reflective electrode).

An interlayer insulating film 521 is selectively formed by a dropletdischarge method as in Embodiment Mode 2. In the pixel area, theinterlayer insulating film is formed so as to cover the area except thepart later to be a pixel electrode. Droplet discharge and bake may berepeated two or more times to make the interlayer insulating film thickenough. In the terminal area, the interlayer insulating film 221 isprovided so as not to cover the part later to be a terminal electrode.Thus, the interlayer insulating film is not provided in the areas whereconnection is made or the insulating film is not required. Accordingly,the formation of contact holes is redundant.

Next, a terminal electrode 544 in contact with a connection wiring 541is formed by a droplet discharge method or printing.

Through the above steps, a TFT substrate for a reflective liquid crystaldisplay panel in which a bottom gate (inverted staggered) TFT and apixel electrode are formed over a substrate 510 is completed.

Since subsequent steps are the same as Embodiment Mode 2, only briefdescription will be given. An alignment layer 524 a is formed so as tocover the pixel electrode. The surface of the alignment layer 526 a isrubbed thereafter. A counter substrate 525 is provided with a colorfilter including a color layer 526 a, a light shielding layer 526 b, andan over coat layer 527, a counter electrode 528 formed with atransparent electrode, and an alignment layer 524 b thereover. A sealanthaving a closed pattern (not shown) is formed by a droplet dischargemethod so as to surround the portion which is overlapped with the pixelarea. Next, liquid crystal 529 is dropped under reduced pressure so asto prevent bubbles from entering, and the substrates are pastedtogether. Subsequently, unnecessary part of a substrate is separated.Further, FPC 546 is pasted with an anisotropic conductive layer 545 inbetween by a known method. A reflective liquid crystal module can becompleted through the above steps (FIG. 5).

As described above, according to this embodiment, the light exposureusing a photomask is skipped by selectively forming an interlayerinsulating film by a droplet discharge method; thus, the process can besimplified and the time of manufacture can be reduced.

In this embodiment, a part of the pattern of the drain wiring serves asa pixel electrode; therefore, a contact between the drain wiring and apixel electrode is not required to be made, which results in thesimplification of the process.

In this embodiment, a process in which a light exposure process using aphotomask is not carried out; however, a part of patterning may beperformed by light exposure using a photomask. For example, if aphotomask used in a patterning step of removing a part of thesemiconductor film, by which the size of a channel region is determined,the size can be determined finely.

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, or Embodiment 1.

Embodiment 3

In this embodiment, an example of manufacturing an active matrix liquiddisplay device using a channel etch TFT will be shown. FIG. 6 shows across section of a liquid crystal display device according to thisembodiment.

Since this embodiment is similar to Embodiment Mode 3 except that theTFT in Embodiment Mode 3 has a channel stop structure. Accordingly, onlysimple explanation will be given here.

Further, a channel etch TFT 630 in this embodiment may be formed throughthe steps according to Embodiment 1.

After the steps up to the formation of a source or drain wiring has beenfinished according to Embodiment 1, a projection (pillar) formed of aliquid repellent (water repellent, oil repellent) material is formedover a part of the source or drain wiring by a droplet discharge methodas in Embodiment Mode 3.

Next, a flat interlayer insulating film 622 is formed. A flat film maybe obtained by using a coating method. Alternatively, the interlayerinsulating film 622 may be formed by a droplet discharge method, andminute irregularities on the surface may be planarized with an airknife. As in Embodiment Mode 3, an interlayer insulating film is formedso as not to be formed on the projections which are repellent to thesolution used for the formation of the interlayer insulating film. Next,contact holes are formed by removing only the projections. Further, apixel electrode 623 in contact with a drain wiring is formed. Similarly,a terminal electrode 644 in contact with the connection wiring 641 isformed.

In the case of manufacturing a transmissive liquid crystal displaypanel, a pattern formed of a composition containing indium tin oxide(ITO), indium tin oxide containing silicon oxide (ITSO), zinc oxide(ZnO), tin oxide (SnO₂), or the like may be formed by a dropletdischarge method, and baked to form the pixel electrode 623 and theterminal electrode 644.

In the case of manufacturing a reflective liquid crystal display panel,the pixel electrode 623 and the terminal electrode 644 can be formed ofa composition mainly containing particles of a metal such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum). Asanother method, a transparent conductive film or a light reflectiveconductive film is formed by sputtering and a mask pattern is formed bya droplet discharge method; thus, the pixel electrode may be formed bycombining etching.

Through the above steps, a TFT substrate for a reflective liquid crystaldisplay panel in which a bottom gate (inverted staggered) TFT 630 and apixel electrode 623 are formed over a substrate 610 is completed.

Since subsequent steps are the same as Embodiment Mode 3, only briefdescription will be given. An alignment layer 624 a is formed so as tocover the pixel electrode. The surface of the alignment layer 626 a isrubbed thereafter. A counter substrate 625 is provided with a colorfilter including a color layer 626 a, a light shielding layer 626 b, andan over coat layer 627, a counter electrode 628 formed with atransparent electrode, and an alignment layer 624 b thereover. A sealanthaving a closed pattern (not shown) is formed by a droplet dischargemethod so as to surround the portion which is overlapped with the pixelarea. Next, liquid crystal 629 is dropped under reduced pressure so asto prevent bubbles from entering, and the substrates are pastedtogether. Subsequently, unnecessary part of a substrate is separated.Further, FPC 646 is pasted with an anisotropic conductive layer 645 inbetween by a known method. A liquid crystal module can be completedthrough the above steps (FIG. 6).

As described above, according to this embodiment mode, the lightexposure using a photomask is skipped by using a projection (pillar)which is liquid repellent; thus, the process can be simplified and thetime of manufacture can be reduced.

In this embodiment, a process in which a light exposure process using aphotomask is not carried out; however, a part of patterning may beperformed by light exposure using a photomask. For example, if aphotomask used in a patterning step of removing a part of thesemiconductor film, by which the size of a channel region is determined,the size can be determined finely.

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 3, or Embodiment 1.

Embodiment 4

In this embodiment, a method for manufacturing an active matrix liquidcrystal display device using a staggered TFT manufactured by a dropletdischarge method as a switching element. FIG. 7 shows a cross sectionalstructure of a liquid crystal display device according to thisembodiment.

First, a base film 711 for improving adhesion with a material layer tobe later formed by a droplet discharge method is formed over a substrate710. The base film 711 may be formed thin; accordingly, it can beregarded as base pretreatment. A photocatalyst (titanium oxide (TiO₂),strontium titanate (SrTiO₃), cadmium selenide (CdSe), potassiumtantalate (KTaO₃), cadmium sulfide (CdS), zirconium oxide (ZrO₂),niobium oxide (Nb₂O₅), zinc oxide (ZnO), iron oxide (Fe₂O₃), tungstenoxide (WO₃)) may be applied with a spray; alternatively, an organicmaterial (polyimide, acryl, or a material having a skeletal structureincluding a bond of silicon (Si) and oxygen (O) which contains at leastone of the group consisting of hydrogen, fluorine, alkyl group andaromatic hydrocarbon as a substituent) may be selectively applied byink-jet method or sol-gel process.

Source and drain wirings 718 a and 718 b are formed over the base film711 by a droplet discharge method. Father, a terminal electrode isformed in the terminal area. As the materials for forming those layers,a composition mainly containing particles of a metal such as gold (Au),silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), tungsten (W),nickel (Ni), tantalum (Ta), bismuth (Bi), lead (Pb), indium (In), tin(Sn), zinc (Zn), titanium (Ti), or aluminum (Al) may be used. Inparticular, the source and drain wirings are preferable to be lowresistance. Therefore, a material in which any one of gold, silver, orcopper dissolved or dispersed in a solvent is preferably used, and morepreferably silver or copper with low resistance is used in considerationof a specific resistance value. However, in the case of using silver orcopper, a barrier film may be additionally provided for an impuritymeasure. A solvent corresponds to ester such as butyl acetate, alcoholssuch as isopropyl alcohol, an organic solvent such as acetone, or thelike. Surface tension and viscosity are appropriately adjusted byadjusting density of a solvent and adding a surfactant or the like.Further, a base layer may be formed as in Embodiment Mode 1.

Subsequently, after an n-type semiconductor layer is formed over theentire surface, a part of the n-type semiconductor layer between sourceand drain wirings 718 a and 718 b is removed by etching.

Next, a semiconductor film is formed over the entire surface. Thesemiconductor film is formed with an amorphous semiconductor film or asemiamorphous semiconductor film which is formed by vapor phase growthor sputtering using a semiconductor material gas typified by silane andgermanium.

Next, a mask is formed by a droplet discharge method, and thesemiconductor film and the n-type semiconductor layer are patterned;thus, a semiconductor layer 714 and n-type semiconductor layers 719 aand 719 b shown in FIG. 7 are formed. The semiconductor layer 714 isformed so as to cover both the source and drain wirings 718 a and 718 b.The n-type semiconductor layers 719 a and 719 b are interposed betweenthe source and drain wirings 718 a and 718 b.

A gate insulating film is formed with a single layer or layeredstructure by plasma CVD or sputtering. As a preferable form inparticular, a gate insulating film may be formed with a stack of threelayers of an insulating layer formed of silicon nitride, an insulatinglayer formed of silicon oxide, and an insulating layer formed of siliconnitride.

Next, a mask is formed by a droplet discharge method, thereby patterningthe gate insulating film 713.

Next, a gate wiring 712 is formed by a droplet discharge method. As aconductive material for forming the gate wiring 712, a compositionmainly containing particles of a metal such as Ag (silver), Au (gold),Cu (copper), W (tungsten), or Al (aluminum) can be used. The gate wiring712 extended to a terminal area is formed so as to be in contact with acorresponding terminal electrode 740 in the terminal area.

A projection (pillar) 720 formed of a conductive material is formed overa part of the source and drain wirings 718 a and 718 b. A stack isformed by repeating discharging and baking of a composition containing aconductive material (such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum)), so that the projection (pillar) 720 isformed. A projection (pillar) 743 is also formed over the terminalelectrode 740 in a similar manner.

An interlayer insulating film which is flat is formed by coating. Theinterlayer insulating film may be formed with an inorganic insulatingfilm such as a silicon oxide film formed by a vapor phase growth methodor sputtering instead of coating. Further, after a silicon nitride filmis formed as a protective film by PCVD or sputtering, the interlayerinsulating film may be formed by coating.

Further, the interlayer insulating film may be formed by a dropletdischarge method before final bake of the projections (pillars) 720 and743; thus, the final bake thereof is carried out simultaneously.

Parts of the interlayer insulating film over the projections (pillars)720 and 743 are removed by etch back of the entire surface, so that theprojections (pillars) 720 and 743 are exposed. Alternatively, theinterlayer insulating film may be grinded by chemical mechanicalpolishing (CMP) and thereafter carrying out etch back of the entiresurface; thus, the projections (pillars) 720 and 743 can be exposed.

A pixel electrode 723 in contact with the projection (pillar) 720 isformed over an interlayer insulating film 722. A terminal electrode 744in contact with the projection (pillar) 743 is similarly formed.

Through the above steps, a TFT substrate for a liquid crystal displaypanel in which a bottom gate (inverted staggered) TFT 713 and a pixelelectrode 723 are formed over a substrate 710 is completed.

Since subsequent steps are the same as Embodiment Mode 1, only briefdescription will be given. An alignment layer 724 a is formed so as tocover the pixel electrode 723. The surface of the alignment layer 726 ais rubbed thereafter. A counter substrate 725 is provided with a colorfilter including a color layer 726 a, a light shielding layer 726 b, andan over coat layer 727, a counter electrode 728 formed with atransparent electrode, and an alignment layer 724 b thereover. A sealanthaving a closed pattern (not shown) is formed by a droplet dischargemethod so as to surround the portion which is overlapped with the pixelarea. Next, liquid crystal 729 is dropped under reduced pressure so asto prevent bubbles from entering, and the substrates are pastedtogether. Subsequently, unnecessary part of a substrate is separated.Further, FPC 746 is pasted to a terminal electrode 744 with ananisotropic conductive layer 745 in between by a known method. Areflective liquid crystal module can be completed through the abovesteps (FIG. 7).

In this embodiment, a process in which a light exposure process using aphotomask is not carried out; however, a part of patterning may beperformed by light exposure using a photomask.

Further, this embodiment can be freely combined with Embodiment Mode 1.

Embodiment 5

In this embodiment, an example of manufacturing an active matrix liquiddisplay device using a channel stop TFT will be shown. FIG. 8 shows across section of a liquid crystal display device according to thisembodiment.

Since this embodiment is similar to Embodiment Mode 2 except that theTFT in Embodiment Mode 2 has a channel stop structure. Accordingly, onlysimple explanation will be given here.

Further, an inverted TFT 830 may be formed through the steps accordingto Embodiment 4. This embodiment includes similar steps to Embodiment 4except for that a part of a pattern of a drain wiring serves as a pixelelectrode (reflective electrode).

Next, an interlayer insulating film 821 is selectively formed by adroplet discharge method as in Embodiment Mode 2. In the pixel area, theinterlayer insulating film is formed so as to cover the area except thepart later to be a pixel electrode. Droplet discharge and bake may berepeated two or more times to make the interlayer insulating film thickenough. In the terminal area, the interlayer insulating film 821 isprovided so as not to cover the part later to be a terminal electrode.Thus, the interlayer insulating film is not provided in the areas whereconnection is made or the insulating film is not required. Accordingly,the formation of contact holes is redundant.

Next, a terminal electrode 844 in contact with a connection wiring 840is formed by a droplet discharge method or printing.

Through the above steps, a TFT substrate for a reflective liquid crystaldisplay panel in which a top gate (staggered) TFT and a pixel electrodeare formed over a substrate 810 is completed.

Since subsequent steps are the same as Embodiment Mode 2, only briefdescription will be given. An alignment layer 824 a is formed so as tocover the pixel electrode. The surface of the alignment layer 826 a isrubbed thereafter. A counter substrate 825 is provided with a colorfilter including a color layer 826 a, a light shielding layer 826 b, andan over coat layer 827, a counter electrode 828 formed with atransparent electrode, and an alignment layer 824 b thereover. A sealanthaving a closed pattern (not shown) is formed by a droplet dischargemethod so as to surround the portion which is overlapped with the pixelarea. Next, liquid crystal 829 is dropped under reduced pressure so asto prevent bubbles from entering, and the substrates are pastedtogether. Subsequently, unnecessary part of a substrate is separated.Further, FPC 846 is pasted with an anisotropic conductive layer 845 inbetween by a known method. A reflective liquid crystal module can becompleted through the above steps (FIG. 8).

As described above, according to this embodiment, the light exposureusing a photomask is skipped by selectively forming an interlayerinsulating film by a droplet discharge method; thus, the process can besimplified and the time of manufacture can be reduced.

In this embodiment, a part of the pattern of the drain wiring serves asa pixel electrode; therefore, a contact between the drain wiring and apixel electrode is not required to be made, which results in thesimplification of the process

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, or Embodiment 4.

Embodiment 6

In this embodiment, an example of manufacturing an active matrix liquiddisplay device using a staggered TFT will be shown. FIG. 9 shows a crosssection of a liquid crystal display device according to this embodiment.

Since this embodiment is similar to Embodiment Mode 3 except that theTFT in Embodiment Mode 3 has a channel stop structure. Accordingly, onlysimple explanation will be given here.

Further, a channel etch TFT 930 in this embodiment may be formed throughthe steps according to Embodiment 4.

After the steps up to the formation of a gate wiring has been finishedaccording to Embodiment 4, a projection (pillar) formed of a liquidrepellent (water repellent, oil repellent) material is formed over apart of the source or drain wiring by a droplet discharge method as inEmbodiment Mode 3.

Next, a flat interlayer insulating film 922 is formed. A flat film maybe obtained by using a coating method. Alternatively, the interlayerinsulating film 622 may be formed by a droplet discharge method, andminute irregularities on the surface may be planarized with an airknife. As in Embodiment Mode 3, an interlayer insulating film is formedso as not to be formed on the projections which are repellent to thesolution used for the formation of the interlayer insulating film. Next,contact holes are formed by removing only the projections. Further, apixel electrode 923 in contact with a drain wiring is formed. Similarly,a terminal electrode 944 in contact with the connection wiring 940 isformed.

In the case of manufacturing a transmissive liquid crystal displaypanel, a pattern formed of a composition containing indium tin oxide(ITO), indium tin oxide containing silicon oxide (ITSO), zinc oxide(ZnO), tin oxide (SnO₂), or the like may be formed by a dropletdischarge method, and baked to form the pixel electrode 923 and theterminal electrode 944.

In the case of manufacturing a reflective liquid crystal display panel,the pixel electrode 923 and the terminal electrode 944 can be formed ofa composition mainly containing particles of a metal such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum). Asanother method, a transparent conductive film or a light reflectiveconductive film is formed by sputtering and a mask pattern is formed bya droplet discharge method; thus, the pixel electrode may be formed bycombining etching.

Through the above steps, a TFT substrate for a liquid crystal displaypanel in which a top gate (staggered) TFT 930 and a pixel electrode 923are formed over a substrate 910 is completed.

Since subsequent steps are the same as Embodiment Mode 3, only briefdescription will be given. An alignment layer 924 a is formed so as tocover the pixel electrode 923. The surface of the alignment layer 926 ais rubbed thereafter. A counter substrate 925 is provided with a colorfilter including a color layer 926 a, a light shielding layer 926 b, andan over coat layer 927, a counter electrode 928 formed with atransparent electrode, and an alignment layer 924 b thereover. A sealanthaving a closed pattern (not shown) is formed by a droplet dischargemethod so as to surround the portion which is overlapped with the pixelarea. Next, liquid crystal 929 is dropped under reduced pressure so asto prevent bubbles from entering, and the substrates are pastedtogether. Subsequently, unnecessary part of a substrate is separated.Further, FPC 946 is pasted with an anisotropic conductive layer 945 inbetween by a known method. A liquid crystal module can be completedthrough the above steps (FIG. 9).

As described above, according to this embodiment, the light exposureusing a photomask is skipped by using a liquid repellent projection(pillar); thus, the process can be simplified and the time ofmanufacture can be reduced.

In this embodiment, a process in which a light exposure process using aphotomask is not carried out; however, a part of patterning may beperformed by light exposure using a photomask.

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 3, or Embodiment Mode 4.

Embodiment 7

In this embodiment, an example in which liquid crystal application isperformed by a droplet discharge method. In this embodiment, an exampleof obtaining four panels from one large area substrate 110 is shown inFIGS. 11A to 11D.

FIG. 11A shows a cross section of a liquid crystal layer being formed byink-jet method. A liquid crystal material 114 is discharged, sprayed, ordripped from a nozzle 118 of an ink-jet system 116 so as to cover apixel area 111 that is surrounded by a sealant 112. The ink-jet system116 is moved to the direction of the arrow in FIG. 11A. Note that, thenozzle 118 is moved here; however, the liquid crystal layer may beformed by moving the substrate while the nozzle is fixed.

FIG. 11B shows a perspective view. The liquid crystal material 114 isselectively discharged, sprayed, or dripped only over the areasurrounded by the sealant 112, and an object surface 115 is movedcorrespondingly to a nozzle scan direction 113.

FIGS. 11C and 11D show enlarged cross sections of an area 119 surroundedby a dotted line in FIG. 11A. When the liquid crystal material 114 hashigh viscosity, it is discharged continuously and applied in a mannerwhere each droplet of the liquid crystal material is joined to oneanother. On the other hand, when the viscosity of the liquid crystalmaterial 114 has low viscosity, it is discharged intermittently and thedroplets are dripped as shown in FIG. 11D.

In FIG. 11C, reference numeral 120 denotes an inversely staggered TFTand reference numeral 121 denotes a pixel electrode. The pixel area 111is formed from a pixel electrode arranged in matrix; a switching elementbeing connected to the pixel electrode, an inversely staggered TFT isused here; and a storage capacitor (not illustrated).

The workflow of manufacturing a panel will be described below withreference to FIGS. 12A to 12D.

First, the first substrate 1035 in which a pixel area 1034 is formedover its insulating surface is prepared. The first substrate 1035 ispretreated with the following steps: forming an alignment layer,rubbing, dispersing spherical spacers, forming a column spacer, forminga color filter, or the like. Subsequently, a sealant 1032 is formed on apredetermined position (a pattern surrounding the pixel area 1034) witha dispenser or an ink-jet system over the first substrate 1035 in aninert atmosphere or under reduced pressure, as shown in FIG. 12A. Amaterial containing fillers (diameter of 6 μm to 24 μm), which has aviscosity of 40 Pa·s to 400 Pa·s, is used for the sealant 1032 that istranslucent. Note that, it is preferable to select a sealant that isinsoluble in a liquid crystal 1033 to be in contact therewith. A photocured acrylic resin or a thermosetting acrylic resin may be used for thesealant 1032. Further, the sealant 1032 can be formed by printing due toits simple seal pattern.

Subsequently, a liquid crystal 1033 is applied to an area surrounded bythe sealant 1032 by ink-jet method. A known liquid crystal material withthe viscosity that allows discharging by ink-jet method may be used forthe liquid crystal 1033. Further, it is suitable to apply a liquidcrystal by ink-jet method since the viscosity of a liquid crystalmaterial can be controlled by adjusting the temperature. The requiredamount of the liquid crystal 1033 can be stored in the area surroundedby the sealant 1032 without a loss.

The first substrate 1035 provided with a pixel area 1034 and the secondsubstrate 1031 provided with a counter electrode and an alignment layerare pasted together under reduced pressure without bubbles being mixedin (FIG. 12C). The sealant 1032 is cured here by heat-treating orapplying an ultra-violet ray while the substrates are pasted together.Note that, heat treatment may be carried out in addition to ultra-violetirradiation.

FIGS. 13A and 13B show an example of a pasting device that is capable ofultra-violet irradiation or heat treatment while or after substrates arepasted.

In FIGS. 13A and 13B, reference numeral 1041 denotes the first substrateholder, reference numeral 1042 denotes the second substrate holder,reference numeral 1044 denotes a window, reference numeral 1048 denotesa downside measuring plate, and reference numeral 1049 denotes a lightsource. Note that, the same reference numerals in FIGS. 12A to 12D areused for the corresponding parts in FIGS. 13A and 13B.

The bottom downside measuring plate 1048 includes a heater, which curesa sealant. The second substrate holder 1042 is provided with the window1044, so that ultra-violet light or the like from the light source 1049can transmit therethrough. Although it is not illustrated here, analignment of a position of the first substrate is performed through thewindow 1044. The second substrate 1031 that is to be a counter substrateis severed into a desirable size, and fixed to the second substrateholder 1042 with a vacuum chuck or the like. FIG. 13A shows a statebefore pasting.

On the occasion of pasting, after the first and second substrate holders1041 and 1042 are lowered, the first substrate 1035 and the secondsubstrate 1031 are pasted together, and ultra-violet light is applied tocure the sealant in the state unchanged where the substrates are pastedtogether. A state after pasting is shown in FIG. 13B.

Next, the first substrate 1035 is cut by means of a cutting machine suchas a scriber, a breaker, or a circular saw (FIG. 12D). Thus, four panelscan be manufactured from one substrate. Further, an FPC is pasted by aknown method.

Note that, the first substrate 1035 and the second substrate 1031 can beformed from a glass substrate, a quartz substrate, or a plasticsubstrate

A top view of a liquid crystal module obtained through the above stepsis shown in FIG. 14A. A top view of another liquid crystal module isshown in FIG. 14B.

A TFT in which an active layer contains an amorphous semiconductor filmhas low field-effect mobility of around 1 cm²/Vsec. Therefore, a drivercircuit for displaying an image is formed with an IC chip, and ismounted in TAB (Tape Automated Bonding) or COG (Chip On Glass).

In FIG. 14A, reference numeral 1101 denotes an active matrix substrate,reference numeral 1106 denotes a counter substrate, reference numeral704 denotes a pixel area, and reference numeral 1105 denotes an FPC.Note that, liquid crystal is discharged under reduced pressure byink-jet method, and a pair of substrates 1101 and 1106 are pastedtogether with the sealant 1107.

In the case where a TFT including an active layer formed with asemiamorphous silicon film is used, a part of a driver circuit may beformed with the TFT, thereby fabricating a liquid crystal module shownin FIG. 11B. Note that a driver circuit which cannot be formed with aTFT including an active layer formed with a semiamorphous silicon filmincludes an IC chip (not shown).

In FIG. 14B, reference numeral 1111 denotes an active matrix substrate,reference numeral 1116 denotes a counter substrate, reference numeral1112 denotes a source signal line driver circuit, reference numeral 1113denotes a gate signal line driver circuit, reference numeral 1114denotes a pixel area, reference numeral 1117 denotes the first sealmaterial, and reference numeral 1115 denotes an FPC. Note that, a liquidcrystal is discharged under reduced pressure by ink-jet method, and apair of substrates 1111 and 1116 are pasted together with the first sealmaterial 1117 and the second seal material. Since a liquid crystal isnot necessary in the driver circuits 1112 and 1113, a liquid crystal isretained only in the pixel area 1114. The second seal material 1118 isprovided to reinforce the whole panel.

A liquid crystal module obtained is provided with a backlight 1204 andan optical waveguide 1205. An active matrix liquid crystal displaydevice (transmissive type) is completed by covering the liquid crystalmodule with a cover 1206. A part of the cross section thereof is shownin FIG. 6. Note that, the cover and the liquid crystal module are fixedwith an adhesive or an organic resin. The polarizing film 1203 is pastedto each of the active matrix substrate and the counter substrate, sincethe liquid crystal display device is a transmissive type.

In FIG. 15, reference numeral 1200 denotes a substrate, 1201 denotes apixel electrode, 1202 denotes a columnar spacer, 1207 denotes a sealant,1220 denotes a color filter which is provided with a color layer and alight shielding film correspondingly to each pixel, 1221 denotes acounter electrode, 1222 and 1223 denote alignment layers, 1224 denotes aliquid crystal layer, and 1219 denotes a protective film.

This embodiment can be freely combined with any one of Embodiment Modes1 to 3 and Embodiments 1 to 6.

Embodiment 8

In this embodiment, an example of a system for droplet discharge isshown in FIG. 16A to 16C. FIG. 16A is a top view. FIG. 16B shows across-sectional view along A-A′ in FIG. 16A. FIG. 16C shows across-sectional view along B-B′ in FIG. 16A.

In FIG. 16A, reference numeral 1601 denotes a substrate, a thin filmtransistor, a pixel electrode, and the like are formed thereover. Thesubstrate 1601 is secured to the substrate stage (not shown). Intransferring the substrate, the substrate is moved in the direction ofthe arrow.

A head 1603 of the droplet discharge system is moved above the surfaceof the substrate 1601, and a solution containing a composition (materialfor forming a metal wiring or an insulating layer) is discharged. Thesubstrate is relatively scanned by moving the head 1603. The head 1603is soaked in a solution in a container 1605 to avoid the clogging.Before scanning, the droplet size and the like are stabled bydischarging on a test stage 1067. When stable droplets are obtained, thehead is moved over to the substrate to discharge.

Alternatively, the head 1603 may be fixed and the substrate 1601 may bemoved for scanning. Solvent of discharged compositions 1604 and 1606 isvolatilized (baked) to form the desired pattern (a metal wiring, aninsulating layer, a mask, and the like).

Here, the entire surface is coated by simply scanning the parallel twoheads 1603 once. However, the head 1603 may be shuttled more than onceto repeat coating.

Further, an example of providing the container 1605 containing asolution and the test stage 1607 is shown here; however, droplets may bedischarged into the container 1605 until the droplets are stabledwithout using the test stage 1607.

FIG. 17 shows an example of nozzles and a control system of a dropletdischarge system.

Each head 1405 a and 1405 b of a droplet discharge means 1403 isconnected to a control means 1407, and the heads are controlled by acomputer 1410; thus, a preprogrammed pattern can be applied. The patternmay be applied based on a marker 1411 formed on a substrate 1400.Alternatively, the edge of the substrate 1400 may be the base. Such baseis detected by an imaging means 1409 such as a CCD, and the informationis converted into a digital signal by an image processing means 1409.The converted digital signal is recognized by a computer and a controlsignal is generated and sent to a control means 1407. The information ofthe pattern to be formed on the substrate 1400 is stored in a storagemedium 1408, and a control signal is sent to the control means 1407based on the information. Thus, each of heads 1405 a and 1405 b of thedroplet discharge means 1403 is individually controlled.

FIG. 17 shows an example in which the heads 1405 a and 1405 b arearranged in two lines perpendicular to the scanning direction.Meanwhile, FIG. 18 shows an example in which heads are arranged in threelines perpendicular to the scanning direction in order to deal with alarge substrate.

In FIG. 18, reference numeral 1500 denotes a large substrate, 1504denotes an imaging means, 1507 denotes a stage, 1511 denotes a marker,and 1503 denotes an area where a panel is to be formed. A pattern of amaterial layer is formed by zigzagging or reciprocating heads 1505 a,1505 b, and 1505 c having the same width as a panel.

In FIG. 18, heads 1505 a, 1505 b, and 1505 c arranged in three linesperpendicular to the scanning direction may discharge differentmaterials for respective material layers, or may discharge one material.When one material is discharged from the three heads to form aninterlayer insulating film to have a pattern, the throughput isimproved.

As to the system shown in FIG. 18, scanning may be performed by moving asubstrate 1500 while a head is fixed, or moving a head while thesubstrate 1500 is fixed.

This embodiment can be freely combined with any one of Embodiment Modes1 to 3 and Embodiments 1 to 7.

Embodiment 9

In this embodiment, examples of each metal particle for forming a metalwiring are shown in FIGS. 19A and 19B. The metal particle is dispersedor dissolved in a solvent; thus, a metal wiring can be formed by adroplet discharge method.

A metal particle shown in FIG. 19A includes copper (Cu) component 1701and silver (Ag) component 1702. Copper is coated by silver; thus,adhesion can be improved in the case of forming a base film orperforming base pretreatment. Further, the irregular surface of coppercan be made smooth by coating with silver.

A metal particle shown, in FIG. 19B includes copper (Cu) component 1711,silver (Ag) component 1712, and NiB is provided therebetween as a bufferlayer 1713. The buffer layer 1713 is provided in order to improveadhesion between the copper (Cu) component and the silver (Ag)component.

This embodiment can be freely combined with any one of Embodiment Modes1 to 3 and Embodiments 1 to 8.

Embodiment 10

In FIG. 20, a mode of electroplating is shown, and the case of obtainingfour panels from a large mother glass substrate will be described.

As shown in FIG. 20A, Ag is applied, for example, by ink-jet method inthe same level as the gate electrode 1303 to form a conductive film 1380for supplying current. The conductive film 1380 may be formed of amaterial different from the gate electrode or may be formed of Cu to betreated with electroplating. Hereupon, Cu may preferably be applied on agate electrode formed of Ag. Consequently, Cu can be formed uniformly byplating.

As shown in FIG. 20B, the substrate 1300 is secured to a stage 1384, anda head 1381 for applying a solution in which metal is dissolved, a head1382 for washing the solution in which the metal is dissolved, and ahead 1383 for spraying a drying gas are sequentially disposed above thesubstrate. By thus arranging a plurality of nozzles, consecutivetreatment can be achieved and throughput can be improved. In the case ofapplying Cu by electroplating, a solution containing copper sulfate anddilute sulfuric acid can be used as the solution in which the metal isdissolved. Oxygen, nitrogen, or the mixture thereof may be used as thedrying gas. Further, hot gas may be sprayed for accelerating drying.

In this state, the substrate 1300 is moved in the direction of thearrow, and electroplating can be performed on the large mother glasssubstrate. The substrate 1300 and the heads 1381, 1382, and 1383 may bemoved relatively.

In the case of applying Cu by electroplating, Cu is provided so as tocoat silver by plating. Since silver is an expensive material, themanufacturing cost can be reduced by thus carrying out copper plating.Further, in the case of manufacturing a large liquid crystal panel, thewiring resistance can be reduced by thus carrying out copper plating.

In the case of carrying out copper plating, the copper plated wiring ispreferably coated with silicon nitride or NIB as a barrier layer.

As shown in FIG. 20C, the substrate 1300 is secured to the stage 1384and arranged slantingly to have an angle of θ. The angle θ may range0°<θ°<90°, preferably, 45°<θ°<80°. Further, the solution may be sprayedfrom the head 1381 with high pressure at an angle ranging 90°<θ°<120°.Similarly, washing water is sprayed from the head 1382, and the gas issprayed from the head 1383 with high pressure. In this case, thesolution drops without flowing on the substrate 1300; accordingly,unevenness of the solution can be avoided. Since the substrate isdisposed slantingly as above, the plating machine is prevented frombeing larger even the mother glass substrate is larger.

Further, the stage 1384 includes conductors and an insulator 1385. Oneof the conductors serves as an anode and the other serves as a cathode.Plating may be performed by flowing current to them. The stage 1384 maybe provided with conductors and an insulator separately.

The plated wiring has a continuous pattern; however, an unnecessary partof the pattern is preferably removed. For example, the pattern is cutinto each wiring in dividing the substrate into each panel.

Plating may be performed by dipping the substrate 1300 in a solution inwhich metal is dissolved.

Further, a conductive film 1302 may be formed around the gate electrodeby electroless plating which does not require current flow due toreduction of metal ions in the solution. In this case, the conductivefilm 1380 used for flowing current is unnecessary.

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, Embodiment Mode 3, or any one of Embodiments 1through 9.

Embodiment 11

A liquid crystal display device and an electronic device of the presentinvention include a video camera, a digital camera, a goggle typedisplay (head mounted display), a navigation system, an audioreproducing device (a car audio, an audio component, and the like), alaptop computer, a game machine, a portable information terminal (amobile computer, a cellular phone, a portable game machine, anelectronic book, or the like), an image reproducing device (specificallya device capable of producing a recording medium such as a DigitalVersatile Disc (DVD) and having a display device that can display theimage) and the like. Especially, it is preferable to apply the inventionto a large-sized television with a large screen or the like. Specificexamples of the electronic devices are shown in FIGS. 21A to 21C.

FIG. 21A is a large-sized display device with a large screen of 22inches to 50 inches, which includes a chassis 2001, a support 2002, adisplay area 2003, and a video input terminal 2005. The display deviceincludes every display devices for displaying information for a personalcomputer, for a TV broadcast reception, and the like. A large areadisplay device which is relatively inexpensive can be acquired even whena large substrate after five generations, which has a side exceeding1000 mm is used.

FIG. 21B is a notebook personal computer, which includes a main body2201, a chassis 2202, a display area 2203, a keyboard 2204, an externalconnection port 2205, a pointing mouse 2206, and the like. A notebookpersonal computer which is relatively inexpensive can be acquiredaccording to the invention.

FIG. 21C is a portable image reproduction device equipped with arecording medium (specifically, a DVD player), which includes a mainbody 2401, a chassis 2402, a display area A 2403, a display area B 2404,a recording medium (a DVD players and the like) reading portion 2405,operation keys 2406, speaker portions 2407, and the like. The displayarea A 2403 mainly displays image information whereas the display area B2404 mainly displays text information. The image reproduction deviceequipped with a recording medium includes home video game machines andthe like. An image reproduction device which is relatively inexpensivecan be acquired according to the invention.

As described above, a liquid crystal display device manufacturedaccording to the invention can be applied to a display area of anyelectronic device. Any liquid crystal display device manufactured usinga structure according to any one of Embodiment Modes 1 through 3, andEmbodiments 1 through 8 can be used for the electronic device of theembodiment.

This embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, Embodiment Mode 3, or any one of Embodiments 1through 10.

Since a plurality of main steps are carried out by a droplet dischargemethod; thus, the manufacturing cost of a manufacturing apparatus can bereduced.

According to the invention, a material layer can be patterned withoutusing a photomask; therefore, the material efficiency is improved.Further, the manufacturing process can be simplified by skipping thesteps of exposure and development in manufacturing a liquid crystaldisplay device. Still further, a liquid crystal display device can beeasily manufactured even when a glass substrate after five generations,one side of which exceeds 1000 mm is used.

1. A method for manufacturing a display device, comprising the steps of:forming a gate electrode by a droplet discharge method; forming a firstinsulating film over the gate electrode; forming a semiconductor filmover the first insulating film; forming a mask over the semiconductorfilm; patterning the semiconductor film using the mask to form apatterned semiconductor film; forming a thin film transistor using thepatterned semiconductor film by forming source and drain electrodes by adroplet discharge method; forming a columnar organic film over one ofthe source and the drain electrodes; forming a second insulating filmcovering the columnar organic film and the thin film transistor;removing the columnar organic film; and forming a pixel electrodeconnecting the one of source and drain electrodes over the secondinsulating film.
 2. The method for manufacturing the display deviceaccording to claim 1, wherein the second insulating film is repellent tothe columnar organic film.
 3. The method for manufacturing a displaydevice according to claim 1, wherein the columnar organic film isremoved by water washing.
 4. The method for manufacturing the displaydevice according to claim 1, wherein the method further comprises a stepof pretreating an area to where the gate electrode is formed.
 5. Amethod for manufacturing a display device, comprising the steps of:forming a gate electrode by a droplet discharge method; forming a firstinsulating film over the gate electrode; forming a semiconductor filmover the first insulating film; forming source and drain electrodes by adroplet discharge method, over the semiconductor film; forming acolumnar organic film over one of the source and the drain electrodes;forming a second insulating film covering the columnar organic film, thesource and the drain electrodes, and the semiconductor film; removingthe columnar organic film; and forming a pixel electrode connecting thesource or drain electrode over the second insulating film.
 6. The methodfor manufacturing the display device according to claim 5, wherein themethod further comprises a step of pretreating an area to where the gateelectrode is formed.
 7. The method for manufacturing the display deviceaccording to claim 5, wherein the second insulating film is repellent tothe columnar organic film.
 8. The method for manufacturing a displaydevice according to claim 5, wherein the columnar organic film isremoved by water washing.
 9. A method for manufacturing a displaydevice, comprising the steps of: forming a gate electrode by a dropletdischarge method; forming a first insulating film over the gateelectrode; forming a semiconductor film over the first insulating film;forming a mask over the second insulating film; patterning thesemiconductor film using the mask to form a patterned semiconductorfilm; forming source and drain electrodes by a droplet discharge method,the source and drain electrode being over the patterned semiconductorfilm; forming a columnar organic film over one of the source and thedrain electrodes; forming a second insulating film covering the columnarorganic film, the patterned semiconductor film, and the source and drainelectrodes; removing the columnar organic film; and forming a pixelelectrode connecting the one of source and drain electrodes over thesecond insulating film.
 10. The method for manufacturing the displaydevice according to claim 9, wherein the method further comprises a stepof pretreating an area to where the gate electrode is formed.
 11. Themethod for manufacturing the display device according to claim 9,wherein the second insulating film is repellent to the columnar organicfilm.
 12. The method for manufacturing a display device according toclaim 9, wherein the columnar organic film is removed by water washing.